<template>
  <!-- 商品分类导航 -->
        <div class="type-nav">
            <div class="container">
                <div @mouseleave="leaveShow">
                    <h2 class="all" @mouseenter="changeShow">全部商品分类</h2>  
                   <transition name='sort'>
                        <div class="sort" v-show="show">
                        <div class="all-sort-list2" @click="goSearch">
                            <div 
                            class="item" 
                            v-for="(c1,index) in categoryList" 
                            :key="c1.categoryId" 
                            @mouseenter="changeIndex(index)"
                            >
                                <h3 :class="{show: currentIndex === index}" >
                                    <a 
                                    :data-categoryname = "c1.categoryName"
                                    :data-category1Id = "c1.categoryId"
                                    >{{c1.categoryName}}</a>
                                </h3>
                                <div class="item-list clearfix" :style="{display: currentIndex === index? 'block' :'none' }">
                                    <div class="subitem" v-for="(c2,index) in c1.categoryChild" :key="c2.categoryId">
                                        <dl class="fore">
                                            <dt>
                                                <a  
                                                 :data-categoryname = "c2.categoryName"
                                                 :data-category2Id = "c2.categoryId"
                                                >{{c2.categoryName}}</a>
                                            </dt>
                                            <dd>
                                                <em v-for="(c3,index) in c2.categoryChild" :key="c3.categoryId">
                                                    <!-- 这里需要注意要把href里需要添加禁止行为  如javascript:; | # | 删掉href -->
                                                    <a 
                                                     :data-categoryname = "c3.categoryName"
                                                     :data-category3Id = "c3.categoryId"
                                                    >{{c3.categoryName}}</a>
                                                </em>
                                            </dd>
                                        </dl>
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
                   </transition>
                </div>  
                <nav class="nav">
                    <a href="###">服装城</a>
                    <a href="###">美妆馆</a>
                    <a href="###">尚品汇超市</a>
                    <a href="###">全球购</a>
                    <a href="###">闪购</a>
                    <a href="###">团购</a>
                    <a href="###">有趣</a>
                    <a href="###">秒杀</a>
                </nav>      
            </div>
        </div>
</template>

<script>
    // 引入mapState获取仓库数据
    import {mapState} from 'vuex'
    // 引入lodash中的throttle  按需引入
    import throttle from 'lodash/throttle'
    export default {
    name:'TypeNav',
    data() {
        return {
            currentIndex:-1,
            // 控制三级联动的显示与隐藏
            show:true
        }
    },
    computed: {
        ...mapState({
            // 参数是vuex中最大的仓库
            categoryList:state=> state.home.categoryList
        })
    },
    methods:{
            changeIndex:throttle(function(index){
            this.currentIndex = index;
            },30),
            goSearch(event){
                // 通过点击事件来获取点击的标签 
                let nodeElement = event.target;
                    // 可以通过节点的dataset属性获取相应节点的自定义属性 返回的是一个kv对象
                    let { categoryname, category1id, category2id, category3id } = nodeElement.dataset;
                    if (categoryname) {
                        // 定义跳转路由携带的参数
                        let location = { name: "search" };
                        let query = { categoryName: categoryname };
                        // 判断是否是一二三哪一级的a标签
                        // 一级标签
                        if(category1id){
                            query.category1Id = category1id;
                        // 二级标签
                        }else if(category2id){
                            query.category2Id = category2id;
                        // 三级标签
                        }else{
                            query.category3Id = category3id;
                        }
                        if(this.$route.params){
                            // 给location对象动态添加一个query属性
                            location.query = query;
                            //params
                            location.params = this.$route.params
                            // 路由跳转
                            this.$router.push(location);
                        }
                        // 比如有params参数也需要携带给search模块
                        // /home->search确实需要有历史记录
                        // search->search不需要有储存历史记录
                        // 这里是判断三级联动是否在home还是search
                        if(this.$route.path!="/home"){
                            this.$router.replace(location);
                        }else{
                            this.$router.push(location);
                        }
                    }
                },
            changeShow(){
                // 这里需要判断路由  如果是home路由则一直是true 反之是search的话就是false
                if(this.$route.path != "/home"){
                    this.show = true;
                }
            },
            leaveShow(){
                this.currentIndex = -1;
                this.show = true;
                if(this.$route.path!="/home"){
                    this.show = false;
                }
            }
        },
        mounted() {
            if(this.$route.path!="/home"){
                this.show = false;
            }
        },
       
    }
</script>

<style scoped lang="less">
  .type-nav {
        border-bottom: 2px solid #e1251b;

        .container {
            width: 1200px;
            margin: 0 auto;
            display: flex;
            position: relative;

            .all {
                width: 210px;
                height: 45px;
                background-color: #e1251b;
                line-height: 45px;
                text-align: center;
                color: #fff;
                font-size: 14px;
                font-weight: bold;
            }

            .nav {
                a {
                    height: 45px;
                    margin: 0 22px;
                    line-height: 45px;
                    font-size: 16px;
                    color: #333;
                    text-decoration: none;
                }
            }

            .sort {
                position: absolute;
                left: 0;
                top: 45px;
                width: 210px;
                height: 461px;
                position: absolute;
                background: #fafafa;
                z-index: 999;

                .all-sort-list2 {
                    .item {
                        h3 {
                            line-height: 30px;
                            font-size: 14px;
                            font-weight: 400;
                            overflow: hidden;
                            padding: 0 20px;
                            margin: 0;

                            a {
                                color: #333;
                                text-decoration: none;
                            }
                            &.show{
                                background-color: #ddd;
                            }
                        }

                        .item-list {
                            display: none;
                            position: absolute;
                            width: 734px;
                            min-height: 460px;
                            background: #f7f7f7;
                            left: 210px;
                            border: 1px solid #ddd;
                            top: 0;
                            z-index: 9999 !important;

                            .subitem {
                                float: left;
                                width: 650px;
                                padding: 0 4px 0 8px;

                                dl {
                                    border-top: 1px solid #eee;
                                    padding: 6px 0;
                                    overflow: hidden;
                                    zoom: 1;

                                    &.fore {
                                        border-top: 0;
                                    }

                                    dt {
                                        float: left;
                                        width: 54px;
                                        line-height: 22px;
                                        text-align: right;
                                        padding: 3px 6px 0 0;
                                        font-weight: 700;
                                    }

                                    dd {
                                        float: left;
                                        width: 415px;
                                        padding: 3px 0 0;
                                        overflow: hidden;

                                        em {
                                            float: left;
                                            height: 14px;
                                            line-height: 14px;
                                            padding: 0 8px;
                                            margin-top: 5px;
                                            border-left: 1px solid #ccc;
                                        }
                                    }
                                }
                            }
                        }

                    }
                }
            }
            // 进入状态:开始阶段
            .sort-enter{
                height:0px;
            }
            // 结束状态:结束阶段
            .sort-enter-to{
                height:461px;
            }
            // 定义过渡动画的时间  这里是定义各种动画及过渡样式
            .sort-enter-active{
                transition: all .3s;
            }
        }   
    }
</style>